ZURICH.- "The results of these further tests are very convincing. They confirm our conclusion that this painting is indeed Leonardos Earlier Version of his Mona Lisa, says Dr. Markus Frey, President of The Mona Lisa Foundation.

Alfonso Rubino, a specialist in the geometry of Leonardo, has recently presented his latest findings which show that Leonardo worked the geometry found in his design of the Vitruvian Man (1487) into his paintings. According to Rubino, the Earlier Mona Lisa portrait embodies the intermediate stage of Leonardos geometric constructions, and therefore must be by Leonardo.

In addition, some skeptics had assumed that the painting was a work of the 17th century; however a new carbon 14 dating test provides a narrower dating window than previous results obtained at Oxford University. It establishes the date of the canvas support to be between 1410 and 1455 and makes these suggestions improbable.

The latest carbon dating test on the canvas of the Earlier Version was performed by the ETH (Swiss Federal Institute of Technology) Zurich and confirms a dating between 1410 and 1455 (95.4% probability) and more precisely within that time range between 1425 and 1450 (68.2% probability). It is therefore highly unlikely that this painting would have been executed beyond the turn of the 16th century, and the first documentary evidence of Leonardo painting Mona Lisa is the eyewitness account of Agostino Vespucci in 1503.

Previously, four tests undertaken by Prof. John Asmus, nuclear physicist, who digitized brushstrokes of both paintings, established scientifically that both the Earlier Version and the Mona Lisa' in the Louvre would have been executed by the same artist. This brushstroke analysis identifies conclusively an artist in the same way that DNA or fingerprints identify criminals.

The new test results and geometrical findings show, as do the previous scientific tests, that suggestions of the painting being a copy of the Mona Lisa painting in the Louvre, are probably misguided. Based on the evidence, it is likely that the portrait in the Louvre derives from this Earlier Version' with Leonardo adding a more complex background and leaving out the side columns.

"When we add these new findings to the wealth of scientific and physical examination results published in our recent book 'Mona Lisa - Leonardo's Earlier Version', I believe anyone will find the evidence of a leonardo attribution overwhelming," adds David Feldman, Vice President of The Mona Lisa Foundation.

The exhibition Mona Lisa: Leonardos Earlier Version? is currently being prepared to be presented to the public by yearend.